Portable electronic imaging systems employing an electronic image display internal to an optical viewing assembly are well known and are generally designed for two primary applications. The most common is the camcorder, comprising a monocular viewfinder to provide a magnified virtual view of the recorded scene. Such viewfinders provide only a limited apparent field of view and a limited exit pupil and eye relief, and further limit viewing to one eye, resulting in an inconvenient configuration for the user and limited utility for other applications. One solution to this problem has been to replace the viewfinder with a larger flat television display. This solution provides comfortable viewing by both eyes with no exit pupil and eye relief restrictions. However, a large display costs and weighs significantly more than the conventional viewfinder, requires a great amount of battery power, and also provides only a limited field of view.
The second common application of optical viewing assemblies in electronic imaging systems is the head mounted display for night vision or virtual reality applications. Typically employing a binocular or biocular optical system to view one or two display panels, such systems generally provide wider fields of view (i.e., greater than 40.degree.) and larger exit pupils than camcorder viewfinders by employing more elaborate and expensive optical systems, larger display panels, or both. However, the greater cost of such systems combined with the limited utility of head mounted displays results in restricted markets and subsequently in restricted development and production resources.
Another significant problem which is common to both such portable electronic imaging systems is their limited utility, thereby restricting one application from sharing in the benefits of another. Simply stated, camcorders can not realistically enjoy the advantages of head mounted display imaging systems because such systems are too elaborate or too expensive. Conversely, head mounted display systems inherently do not benefit from the large market demand and the subsequent resources of the camcorder industry.
These imaging systems further share an inability to be upgraded with advances in display technology, requiring the user to purchase an entire new imaging system to exploit such advances.
Finally, it is well known that camcorders exhibit many characteristics which are often undesirable, including excessive weight, size, cost and incompatibility with different tape formats. Current camcorders also provide only monaural sound, requiring separate headphones to listen to the stereo capabilities inherent in such systems. Current camcorders also require the user to manage the camcorder's weight significantly from their body, causing greater fatigue than if one's hands are maintained more closely. Further, the narrow viewfinders of most camcorders may represent particular danger to the user's eye if the camcorder is bumped or if the user is in a dynamic situation. Such viewfinders also are inconvenient and sometimes difficult to use by people who wear eyeglasses. In addition, viewfinder/displays of conventional camcorders do not provide supplemental utility as a monitor which can be viewed simultaneously by multiple persons.